1. Field of Invention
The present invention relates to optical switching and, more particularly, to an optical switching system, device, and method using bandpass filters and mirrors.
2. Description of Related Art
Optical communication systems are a substantial and rapidly growing part of communication networks. The expression xe2x80x9coptical communication system,xe2x80x9d as used herein, relates to any system that uses optical signals to convey information across an optical transmission device, such as an optical fiber. Such optical systems may include, but are not limited to telecommunication systems, cable television systems, and local area networks (LANs).
While the need to carry greater amounts of data on optical communication systems has increased, the capacity of existing transmission devices is limited. Although capacity may be expanded, e.g., by laying more fiber optic cables, the cost of such expansion is prohibitive. Consequently, there exists a need for a cost-effective way to increase the capacity of existing optical transmission devices.
Wavelength division multiplexing (WDM) has been adopted as a means to increase the capacity of existing optical communication systems. In a WDM system, plural optical signals are carried over a single transmission device, each channel being assigned a particular wavelength.
An essential part of optical communication systems is the ability to switch or route signals from one transmission device to another. For example, micro-electromechanical mirrors have been developed for routing signals between transmission devices. This technique operates by changing the angular orientation of the mirrors, thereby reflecting signals to different locations. Designers have also considered using bubbles that are capable of changing their internal reflection for switching optical signals. However, these techniques are unable to switch between multiple wavelengths. Furthermore, both of these devices have limited switching speeds, in the range of 10 kHz for the mirror devices and in the range of 100 Hz for the bubble devices.
Zigzag multiplexers are also well known in the art for transmitting signals on multiple transmission devices. For example, U.S. Pat. No. 6,008,920 discloses a multiplexer/demultiplexer device that utilizes a filter that is sensitive to the angle of incidence of light. However, such multiplexers have not been used for switching or routing applications in conjunction with arrays of fibers, detectors, and emitters.
Other switching approaches, such as the approach disclosed in U.S. Pat. No. 4,769,820, issued to Holmes, can switch data at GHz rates, which is effectively switching at GHz transition rates. However, this approach requires substantial optical switching power, has potential cross talk, and cannot resolve wavelength over-utilization issues. What is needed is a means for switching wavelength division multiplexed signals that is capable of doing so at high speeds with no cross talk and requires low switching power. What is also need is a switch device that is capable of switching large numbers of signals.
1. Advantages of the Invention
One advantage of the present invention is that it is able to switch signals of different wavelengths.
Another advantage of the present invention is that it is able to switch at high speeds.
A further advantage of the present invention is that it does not require high power.
An additional advantage of the present invention is that it does not suffer from crosstalk.
Another advantage of the present invention is that it is able to switch between wavelengths and fibers to avoid transmission device or wavelength over-utilization.
Another advantage of the present invention is that it is able to broadcast to multiple transmission devices or couplers simultaneously.
A further advantage of the present invention is that it is able to regenerate, reshape, retime, and restore signals.
An additional advantage of the present invention is that it can transmit through air or other intervening media to a receiver without a costly or slow electrical interface.
Another advantage of the present invention is it is able to efficiently switch a large volume of signals.
These and other advantages of the present invention may be realized by reference to the remaining portions of the specification, claims, and abstract.
2. Brief Description of the Invention
The present invention comprises a plurality of optical signal carriers including at least one source and at least one target. A source is adapted to transmit an optical signal to the optical switch element and a target is adapted to receive the optical signal from the optical switch element. Each carrier is adapted to communicate an optical signal.
A plurality of switch elements is also provided. Each switch element is adapted to receive an optical signal from a source and transmit the optical signal to a target.
An imaging unit is provided for each switch element. Each imaging unit includes a first imaging lens and a second imaging lens, a mirror for reflecting an optical signal from the first imaging lens to the second imaging lens, and a bandpass filter. Each bandpass filter is adapted to receive light from the second imaging lens and allow light within a predetermined range of wavelengths to pass through the band pass filter to a respective switch element and to reflect light outside of the predetermined range of wavelengths to another imaging unit.
The above description sets forth, rather broadly, the more important features of the present invention so that the detailed description of the preferred embodiment that follows may be better understood and contributions of the present invention to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.